Merge branch 'master' into python3

diff --cc wrw/dispatch.py
index 5276892,f0326cb..2ece093
--- 1/wrw/dispatch.py
--- 2/wrw/dispatch.py
+++ b/wrw/dispatch.py
@@@ -17,8 -17,9 +17,9 @@@ def mangle(result)
      return [str(result)]
  
  def defaulterror(req, excinfo):
 -    import resp
 +    from . import resp
      traceback.print_exception(*excinfo)
+     sys.stderr.flush()
      raise resp.httperror(500)
  
  def wraphandler(handler, excinfo):